/Engine/Source/Runtime/UMG/Public/Components/WidgetInteractionComponent.h
Press a key as if it had come from the keyboard. Avoid using this for 'a-z|A-Z', things like the Editable Textbox in Slate expect OnKeyChar to be called to signal a specific character being send to the widget. So for those cases you should use SendKeyChar.
virtual bool PressKey ( [FKey](API\Runtime\InputCore\FKey) Key, bool bRepeat )